Plasma generating devices play an important role in many areas. For example, plasma is used in displays, such as television sets and computer monitors, spectrography, in spraying applications such as coating, and in medicine. In medicine, plasma is used for pain relief, prevention of infection spread, and surgery.
Three basic tasks that a surgeon performs during a surgery are cutting, vaporizing and coagulating tissue. Generally, cutting refers to the separation of the tissue; vaporization refers to the controlled destruction of tissue; and coagulation refers to the stopping of bleeding from the tissue or blood vessels in the tissue. Most open, and even laparoscopic, surgeries involve cutting and coagulating tissue. Some surgeries, such as the removal of tumor nodules, also involve vaporizing tissue.
The use of plasma to accomplish these three tasks is known in the art. In general, to accomplish these tasks, a plasma flow is directed at the treated tissue, which accomplishes certain thermal effects in the tissue. For cutting and vaporization these thermal effects are the sublimation and removal of tissue. For coagulation, the desired thermal effect is the creation of a sealing layer of necrotic tissue that prevents further bleeding. Although plasma is considered to be a superior way of accomplishing the three tasks, some problems with using plasma still remain.
Presently, a surgeon typically uses a dedicated device for each of the three surgical tasks. While this ensures that each device is well adapted to the function it is performing, switching from one task to another requires changing devices. In a typical procedure the surgeon will constantly need to switch from one function to the other, as cutting and vaporizing tissue exposes new bleeding tissue that must be coagulated. Changing devices during surgery adds to the duration and complexity of the procedure, and increases the risk to the patient. In laparoscopic surgery in particular, where the devices are miniaturized and are inserted into the patient's body cavities, changing devices frequently is problematic. Presently, there are no known devices capable of performing all three functions well enough for a surgeon to forgo the use of specialized devices in favor of a single, all-in-one, device.
Even the use of specialized plasma surgical devices has underlying problems. For example, a plasma device specifically adopted for cutting had to have a small outlet diameter that results in a turbulent plasma flow suitable for cutting. The small outlet diameter makes such devices unusable for coagulation that generally requires relatively large spot diameter. Further, cutting of the tissue with such a device results in bleeding that not only impairs the surgeon's visibility of the treated tissue, but, if not timely stopped, was dangerous to the patient. As another example, plasma devices adopted for coagulation could not stop high-rate bleedings. Stopping even medium-rate bleeding requires significant experience with the device.
Accordingly, there is a need in the art for systems and methods that allows improved control over the volumetric properties of plasma flows. In particular, there is a need for systems and methods that would accomplish the three surgical tasks of cutting, vaporization, and coagulation. Preferably, the system and method would perform the three surgical tasks at least as well as the presently known devices.